Porous concrete structures are conventionally, for example, made of cement, rough aggregates and water, and each of which is kneaded and cured to be used for water permeable pavements or draining pavements.
However, the porous concrete structures have such an arrangement in which each of the rough aggregates is connected with cement paste and kept in contact at a point. As a result, the porous concrete structures are low in both flexural strength and compressive strength and also it is difficult to increase resistance to fly loss. In other words, for a pavement made of the porous concrete structure having the above arrangement it easily causes fly loss of rough aggregates locating on the surface thereof when a big stress is applied to the surface thereof every time vehicles frequently brake.
Further since the porous concrete structures have a porous arrangement, resistance to a freeze-thaw effect is very low. Therefore, it is not recommendable to use the porous concrete structures in a cold district.